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Sunday 10 December 2017 at 00:37
Oh shite!
I forgot about that 8.5K resistor.
Of course it will read as 75V -- that 8.5K resistor *IS* the load.
If you pull the plug from J3 - it will go back high.
Bad cap for HV (1200u @ 250V) is possible as is a bad resistor but not likely.
I'm willing to bet Q1 is bad.
Source: http://pinside.com/pinball/forum/topic/i-really-need-you-help-power-switching-board-issue#post-4115770